| 摘要 |
<p>PURPOSE:To prevent the whitening of a plastic lens and deterioration in optical function due to coloring and the like of a cooling liquid even when used for a long time by using a cooling liquid comprising polyhydric alcohol and of water soluble polymer, and whose amount of the water soluble polymer is specified. CONSTITUTION:A cooling liquid comprising polyatomic alcohol and water soluble polymer, whose amount of water soluble polymer is 0.0001-4.5weight%, is used. Ethylene glycol or diethylene glycol and the like is used as polyatomic alcohol, and it is preferred that at least two species are mixed together, in consideration of a freezing point for the use in a cold region. As water soluble polymer, polyvinyl alcohol, methylcellulose and so on, can be used. The amount of water soluble polymer is preferred to be in a range of 0.001-4.5weight%, and more preferably, it should be in a range of 0.1-2weight%. The whitening of a plastic lens, and the deterioration in optical function due to the coloring of a cooling liquid and the like does not occur, even when used for a long time.</p> |
